This invention relates to an anti-theft system, and more particularly to an anti-theft device which is also used to obtain authorized entry and which operates without the use of a key.
Numerous burglary prevention systems are presently available for guarding a premises such as a house, building or the like. Many of these systems operate under control of a key which is maintained by the authorized user. The key is utilized to arm the system as well as to disarm the system. Entry into the premises can only be achieved by disarming the burglar alarm system with the prescribed key. After the burglar alarm is disarmed, a separate key must be used to obtain entry into the premises. However, as is well known, it is relatively easy to obtain a counterfeit key to fit the burglar system lock as well as the regular lock. Once such a counterfeit key is made, the burglar alarm can be disarmed and unauthorized entry to the premises can be obtained.
Other types of burglar alarms utilize a combination lock which may use a keypunch type of entry device, wherein numbers are depressed in accordance with a predetermined sequence to obtain entry into the premises. However, such systems have a limited number of possible combinations due to the limited number of buttons which can be placed on the device. Increasing the number of buttons also increases the complexity of the circuitry and the cost involved. As a result, most of these burglar alarm systems utilize simple combinations with relatively few number of possible combination of numbers. Furthermore, even after the combination lock is opened, a regular key type lock is still utilized to obtain authorized entry into the premises.
It is therefore an object of the present invention to provide an anti-theft system which avoids the aforementioned problems of prior art devices.
A further object of the present invention is to provide an anti-theft system which will provide maximum security to homes, buildings and the like and eliminate the necessity of utilizing a key operated locking device for entry and exit into the premises.
Yet another object of the present invention is to provide an anti-theft system which utilizes a selector switch having a combination of buttons for depression as well as a rotary dial with numbered positions; wherein the combination is determined by the selection of the proper sequence of buttons in conjunction with the selection of a preset position on the rotary dial for each button depressed.
Yet a further object of the present invention is to provide an anti-theft system which includes a selector switch device exterior of the premises as well as a similar device interior of the premises, both of the devices being coupled together.
Yet another object of the present invention is to provide an anti-theft system which utilizes a unique selector switch device for obtaining entry into the premises.
A further object of the present invention is to provide an anti-theft system which requires carrying out a prescribed sequence of steps to obtain entry, wherein each step provides an energy source for the next step, and wherein an error on any one of the steps makes it impossible to carry out the next step and also necessary to repeat the entire sequence of correct steps.
Another object of the present invention is to provide an anti-theft system which provides an indication when the system is guarding the premises as well as a separate indication when the premises can be used for authorized entry and exit.
A still further object of the present invention is to provide an anti-theft system having a first guarding position which only permits entry by opening of a prescribed combination and which has a second monitoring position which only permits entry into the premises by the use of an additional switching device.
Another object of the present invention is to provide an anti-theft system which is rugged in construction, inexpensive to manufacture and install, easy to manipulate, and efficient and reliable in operation.
These and other objects, features and advantages of the invention, will, in part, be pointed out with particularity, and will, in part, become obvious from the following more detailed description of the invention, taken in conjunction with the accompanying drawings, which form an integral part thereof.